Crimped composite fibers and process for preparation thereof

ABSTRACT

CRIMPED COMPOSITE FIBERS HAVING A LARGE NUMBER OF CRIMPS, HIGH CRIMPS ELONGATION, HIGH CRIMP STRENGTH, HIGH OBTAINED BY SPINNING A HOMOPOLYAMIDE COMPONENT AND A TERPOLYAMIDE COMPONENT PRODUCED BY POLYMERIZING E-CAPROLACTAM, HEXAMETHYLENEDIAMMONIUM ADIPATE (66 SALT) AND HEXAMETHYLENEDIAMMONIUM TEREPHTHALATE (6 T SALT), THE COMPOSITION OF SAID COPOLYMER FALLING WITHIN A SPECIFIED AREA IN A TRIANGULAR COORDINAGE INTO FIBERS THROUGH A COMMON SPINNEREL, STRETCHING THE RESULTANT FIBERS AND SUBJECTING THE DRAWN FIBERS TO HEAT TREATMENT

March 13, 1973 YOSH|SATO FUJISAKI ET AL 3,720,576

CRIMPED COMPOSITE FIBERS AND PROCESS FOR PREPARATION THEREOF Filed March 1, 1967 A M J 90 {AAA 2; 9000 70 60 504030 20/0 B United States Patent 3,720,576 CRIMPED COMPOSITE FIBERS AND PROCESS FOR PREPARATION THEREOF Yoshisato Fujisaki, Noboru Fukuma, Hiroshi Chayamiti,

Toshio Okamoto, Seizaburo Shigeta, and Takanobu Kitago, Nobeoka-shi, Japan, assiguors to Asahi Kasei Kogyo Kahushiki Kaisha, Kita-ku, Osaka, Japan Claims priority, application Japan, Mar. 11, 1966,

41/14,671; Oct. 17, 1966, ll/67,874, 41/67,873;

Dec. 1, 1966, ll/78,365

Int. Cl. Dllld 5/12; 1329f 3/10 US. Cl. 161-173 Claims ABSTRACT OF THE DISCLOSURE Crimped composite fibers having a large number of crimps, high crimp elongation, high crimp strength, high crimp developing capability and high bulkiness can be obtained by spinning a homopolyamide component and a terpolyamide component produced by polymerizing e-caprolactam, hexamethylenediammonium adipate (66 salt) and hexamethylenediammonium terephthalate (6 T salt), the composition of said copolymer falling within a specified area in a triangular coordinate, into fibers through a common spinneret, stretching the resultant fibers and subjecting the drawn fibers to heat treatment.

The present invention relates to crimped composite fibers consisting of a homopolyamide and a terpolyamide produced by polymerizing e-caprolactam (referred to as 6 M), hexamethylenediammonium adipate (referred to as 66 salt) and hexamethylenediammonium terephthalate (referred to as 6 T salt), the composition of said copolymer falling within a specified area in a triangular coordinate, and further relates to a process for producing the same.

A process for producing crimped composite fibers is known which comprises separately preparing two dilferent polymer spinning solutions, extruding the solutions through a common spinneret without thoroughly mixing them, drawing the resultant fibers and subjecting the drawn fibers to relaxation or to heat treatment in a relaxed state.

For example, US. Pat. No. 2,439,814 discloses composite fibers of viscose, protein, cellulose ethers, cellulose esters, polyamide compounds and polyvinyl compounds. In this case a crimped yarn can be obtained by drawing the spun filaments beyond the limit of elasticity of at least one component and treating the drawn filaments with a swelling agent or subjecting same to heat treatment. The two different polymers may be those which are different in kind, molecular weight, viscosity of the polymer solution or the like. However, there is no specific teaching in the above patent relating to the use of a polyamide copolymer. Further, there is no description of such characteristics of the resultant crimped yarn as the number of crimps, crimp elongation, crimp strength, etc.

Japanese patent publication No. 7,260/ 1964 discloses a process for producing crimped composite fibers which comprises spinning either two polyamides diiferent in chemical composition or a combination of a polyamide and a polyester into composite fibers, drawing the resultant yarn at a temperature at most 60 C. lower than the melting point of the lower melting component, removing the tension and subjecting the yarn to heat treatment in a relaxed state. According to this process crimped yarn is obtained which requires a force of about 6.6 mg./d. to remove one half of the crimp. Thus, this yarn has substantially similar crimp strength to that of yarns obtained by a twisting and untwisting process which has been previously known as a textured process. There are, however,

3,720,576 Patented Mar. 13, 1973 described as polymers used in this specification only nylon- 66, nylon-6, nylon-610, nylon-ll and the like.

Further, Japanese patent publication No. 15,847/1965 discloses that crimped yarn consisting of two components sufficiently bonded to each other can be obtained by spinning poly-e-caprolactam and a copolymer of e-eaprolactam and hexamethylenediammonium terephthalate into a composite fiber, drawing the resultant fiber and relaxing the drawn fiber. There is, however, substantially no concrete description relating to the crimp characteristics of the product, such as the number of crimps, crimp elongation, crimp strength, crimp developing capability and the like.

An object of the present invention is to provide, from poly-e-caprolactam and a terpolyamide, a crimped yarn having distinguished crimp developing capability and great crimp strength or to provide a nylon composite fiber equivalent to textured yarn obtained by previous falsetwisting method, having great crimp strength, high bulkiness and an appropriate size of crimps.

The terms employed in the present specification are defined as follows.

Relative viscosity (1 rel) can be calculated using the following equation:

Relative viscosity (17 rel)=t /t wherein t represents the drop time (seconds) of a solution of one gram of a polymer in 100 ml. of 95.5 percent concentrated sulfuric acid measured at 25 C. by Ostwalds viscometer, and t represents the drop time (seconds) of the 95.5 percent concentrated sulfuric acid alone.

Number of crimps represents the number of crimps per 25 mm., counting the space between adjacent peaks or bottoms as one crimp when crimped yarn is subjected to an initial load of 2 mg./d.

Crimp elongation can be calculated from the following equation:

Crimp Elongation X 100 wherein L is the distance between two points marked on crimped yarn when the yarn is subjected to an initial load of 2 mg./d., and L is the elongated distance between said two points when the yarn is subjected to a load of 50 mg./d. instead of the initial load.

Crimp strength is defined as the load (mg./d.) for an elongation of L50 L2 X50 percent. The crimp strength can be determined by the following procedure:

The length L under the initial load changes to L L L L and L respectively, when the load is successively replaced by 5, 10, 20, 30 and 50 mg./d. A load-elongation curve is then obtained by plotting the values of 5 2 ID 2 20 2 100 x100. L2 x100,

X 100 (percent) can be readily read from the above curve.

Crimp developing capability is represented by the number of crimps as defined above, which are measured after the yarn has been treated with steam at C. for 30 minutes under the above-mentioned initial load.

According to the present invention there is provided a process for producing crimped yarn having an excellent number of crimps, crimp elongation, crimp strength, crimp developing capability, bulkiness and the like which comprises extruding two spinning solutions, wherein poly-e-caprolactam or polyhexamethylene-adipamide and a terpolyamide of at least 6 M, 66 salt and 6 T salt are present respectively independently, through a common spinneret in a customary composite spinning apparatus, taking up the resultant yarn, and subjecting the yarn to a hot or cold drawing procedure followed by heat treatment.

Crimped yarns having the further improved properties described above can be obtained by limiting the composition of the terpolyamide consisting of at least 6 M, 66 salt and 6 T salt to a composition which falls within a specified area in a system of triangular coordinates.

The accompanying drawing is a triangular coordinate system showing the composition range of the terpolyamide employed in the present invention.

In the drawing, the three sides of the triangular coordinate represent the contents in mol percent of 6 M, 66 salt and 6 T salt in the copolymer, respectively. The preferred terpolyamide has the composition which falls within the area bounded by polygon ABCDEA. If the composition is varied within this range, different crimped yarns are obtained in which one or more of the desired properties such as, for example, distinguished crimp developing capability, great crimp strength, high bulkiness, large crimp elongation, good crimp elongation recovery and the like are obtained according to the respective compositions.

For example, if a terpolyamide is employed having a composition within the area bounded by triangle AFGA or polygon HIJKH, crimped yarn can be obtained having high bulkiness and good recovery. If a terpolyamide is employed having a composition within an area bounded by polygon LKMNOL, a crimped yarn can be obtained having excellent crimp developing capability and great crimp strength. Respective points in the drawing are shown in the following table.

The terpolyamide employed in the present invention may be obtained by charging into an autoclave a mixture of 6 M, 66 salt and 6 T salt in a ratio within the polygon in the triangular coordinate system, adding 20 weight percent or more of water to the mixture, if necessary, heating at 200 to 220 C. for several hours at an increased pressure, preferably for two to five hours, raising the temperature to 250 to 300 C. while gradually venting the vapor to keep the pressure constant, and then heating the mixture to 250 to 300 C. at atmospheric pressure for several hours to scores of hours, preferably over ten hours. The other component of the fiber, i.e., poly-e-caprolactam or polyhexamethylene adipamide, may be produced by a usual polymerization method. Both of the components may contain known additives such as a stabilizer, a pigment and the like.

In order to obtain composite fibers, a melt composite spinning apparatus having known spinnerets is used. Thus two polymer components, which have been separately melted, are combined just ahead of the spinneret and are then extruded through the spinneret into a cooling bath such as air and water baths to produce composite yarn.

Preferred modes of combining these two polymers include side by side type wherein they are bonded like a bimetal and eccentric sheathed core type wherein one polymer forms a core surrounded by the other polymer. The volume ratio of the components may be varied within the range of 2:8 to 8:2.

For takin up and drawing the resultant yarn, the processes for poly-e-caprolactam or polyhexamethylene adipamide yarn alone can be utilized as such. When a low melting copolymer having a composition within the range defined by the area of polygon GFPQG in FIG. 1 is employed as one component, an oil having a very low moisture content not more than 20 weight percent which is heated, if necessary, at 40 to C. should be used as a spinning oil. Otherwise, the drawing process becomes difficult to carry out because the undrawn yarns are stuck together on the winding bobbin. The object in heating the oil is to reduce the viscosity of the oil in order to obtain uniform undrawn yarn. When such an oil is employed, usual methods can be applied without presenting any difficulty to subsequent drawing and twisting processes even if a copolymer having a composition within the polygon GFPQG is employed.

Either cold drawing or hot drawing can be applied to the undrawn yarn.

If it is desired that the drawn yarn produce no crimps immediately after the yarn is relaxed, cold drawing is preferable. On the other hand, if it is desired that the drawn yarn recover crimps immediately after the yarn is relaxed, hot drawing at a temperature of 60 C. or higher is preferred. Although hot drawing can produce useful crimped yarn by itself, a further greater improvement in the crimps can be obtained by subjecting the drawn yarn to heat treatment in a relaxed condition. In case of cold drawing, subsequent heat treatment in a relaxed condition or under a load of about 0.5 mg./d. is necessary to obtain yarn of good crimpiness. In some cases heat treatment under a load of about 0.5 mg./d. gives yarn having a larger number of crimps than heat treatment in a relaxed condition. It has been heretofore a matter of common knowledge that heat treatment under no load gves crimped composite yarn having a larger number of crimps. The fact that the above-mentioned heat treatment under a small load gives a yarn having a larger number of crimps, therefore, shows a special feature of the crimped yarn of the present invention.

The hot treatment temperature may be 60 to 180 C. If hot water or steam is used as a heating medium, 80 to C. is preferable. The heating media which may be used here include air and other fluids in addition to hot water and steam. The results of our studies have shown that the yarn produced by the process described in Japanese patent publication No. 15,847/65 has a crimp strength as defined above of at most 6 to 7 mg./d., number of crimps 0f 30 and crimp producing capability of about 30. On the other hand, the yarn obtained by spinning and drawing procedures under the same condition according to the present invention has a crimp strength of not less than 13 mg./d., number of crimps of about 70 and crimp producing capability of 60. Crimped yarn having such a large number of crimps has never been obtained even if a copolymer of 6 M and 66 salt and poly-@- caprolactam or polyhexamethylene adipamide are subject to a composite spinning procedure.

If a terpolyamide within a range rich in 6 M or 66 salt is employed in the present invention, a crimped yarn having such high crimp elongation as 300 percent or more or that of an excellent bulkiness can be obtained. If a terpolyamide within a range rich in 6 T component is employed, crimp yarn having a hard touch can be obtained.

The crimped yarn obtained according to the resent invention possesses the additional advantage of having good dyeability. Its dyeability with acid dyes, direct dyes and so forth are more excellent than that of yarn of nylon 6 alone.

The following examples illustrate the present invention.

EXAMPLE 1 A mixture of 734 grams of 6 M, 262 grams of 66 salt and 705 grams of 6 T salt respectively in a powdery state (the molar ratio of 6 M, 66 salt and 6 T salt was 65:10:25) was charged into an autoclave. After purging the autoclave with nitrogen, the mixture was heated at 220 C. under an increased pressure for two hours. The temperature was gradually increased to 280 C. while venting the vapour to keep the pressure constant. At this temperature the pressure was further released until it dropped to atmospheric pressure. Heating was continued for hours under a nitrogen stream. The contents were extruded in a ribbon-like form from the autoclave under an increased pressure of nitrogen and was pelletized followed by an extraction procedure with hot water. Thus, terpolyamide pellets were obtained having a relative viscosity 1; rel of 2.8 and a melting point of 200 C.

In the meantime 6 M was polymerized according to a known method and was subjected to a extraction procedure with hot water to otbain nylon 6 polymer pellets having a relative viscosity 1; rel of 2.9.

These two polymers were extruded through a known spinneret for composite spinning having one orifice of 0.5 mm. in diameter at 300 C. as a side by side type in portions of equal volume. The resulting yarn was taken up at the rate of 300 m./min. Thus, 45 d./1 f. composite undrawn yarn was obtained.

The yarn was then drawn at 400 m./min., a draw ratio of 3.0 and a drawing temperature of 20 C. using a known draw-twister. When drawn yarn thus obtained was unwound from the bobbin and was then relaxed, it showed a gentle curve but was substantially straight. When the yarn was treated with steam at 80 C. under no tension for one hour, excellent crimped yarn having a number of crimps of 67, crimp elongation of 135 percent, crimp strength of 15.5 mg./d. and crimp developing capability of 60 was obtained. Alternatively, the yarn was subjected to the same heat treatment under a load of 0.5 mg./d. and crimped yarn having a number of crimps of 80 was obtained.

For the comparison with crimped yarn obtained above, a copolyamide was prepared as follows:

Polymerization was carried out in the same manner as mentioned above except that a mixture of 922 grams of 6 M and 260 grams of 6 T salt (a molar ratio was 90:10) was copolymerized. Thus a copolyamide was obtained having a relative viscosity 7; rel of 2.7 and a melting point of 200 C. The copolyamide was subjected to composite spinning procedure and the resultant yarn was then subjected to drawing and heat treatment procedures in the same manner as mentioned above. The resultant crimped yarn had crimp elongation of 156 percent, number of crimps of 30, crimp strength of 6.5 mg./d. and crimp developing capability of 30. The comparison of this result with that of the present invention showed how great the crimp strength of the crimped yarn produced according to the present invention is.

EXAMPLE 2 Polymerization was carried out in the same manner as in Example 1 except that a mixture of 622 grams of 6 M, 602 grams of 66 salt and 620 grams of T salt (molar ratio was 55:23:22) was employed. Thus, terpolyamide pellets having a relative viscosity 1 rel of 2.8 and a melting point of 200 C. was obtained.

The pellets were used in the spinning of composite yarn in the same manner as in Example 1. The resultant yarn was then subjected to drawing and heat treatment procedures. The crimped yarn thus obtained had a crimp elongation of 166 percent, number of crimps of 42, crimp strength of 10.0 mg./d. and crimp developing capability of 40.

The crimped yarn was dyed in a bath (pH was controlled at 5.0 by acetic acid) containing 2% Q.W.F. of Acid Orange II at C. for one hour, Dye absorption was 86 percent. On the other hand, when the yarn of nylon 6 alone was dyed in the same manner, the dye absorption was only 68 percent.

EXAMPLE 3 Copolymerization was carried out in the same manner as in Example 1 except that a mixture of 972 grams of 6 M, 236 grams of 66 salt and 141 grams of T salt (the molar ratio was 86:9:5) was employed. Thus, polymer pellets having a relative viscosity 1 rel of 2.5 and a melting point of 180 C. were obtained. In the meantime 6 M was polymerized according to a usual method in the presence of 0.2 percent of titanium dioxide and the product was extracted with hot water. Thus, nylon 6 polymer pellets having a relative viscosity 1; rel of 2.3 were obtained.

These two polymers were extruded through a known spinneret for composite spinning having 10 orifices of 0.3 mm. in diameter as a parallel type in portions of equal volume. The resultant yarn was taken up at a rate of 500 m./min. using liquid parafiin as a spinning oil. Thus 90 d./ 10 f. composite undra-wn yarn was obtained.

The yarn was drawn at 400 m./min., a draw ratio of 3.0 and a drawing temperature of 20 C. using a known draw-twister.

The drawn yarn was relaxed and then was treated with steam at C. for one hour. Thus, excellent crimped yarn was obtained having crimp elongation of 320 percent and number of crimps of 75.

The above composite undrawn yarn was also drawn on a hot plate at C. at a draw ratio of 3.5 and a rate of 400 m./min. When the drawn yarn was unwound from the bobbin, crimps were produced immediately. Crimp elongation was 70 percent and number of crimps was 25. When the yarn was then treated with steam at 80 C. under no tension for half an hour, crimp elongation became 317 percent and number of crimps 50.

EXAMPLE 4 Copolymerization was carried out in the same manner as in Example 1 except that a mixture of 56 grams of 6 M, 1,700 grams of 66 salt and 846 grams of 6 T salt (the molar ratio was 5:65:30) was used. Thus, terpolyamide pellets having a relative viscosity 1 rel of 2.9 and a melting point of 275 C. was obtained. In the meantime 6 M was polymerized according to a known process and the product was extracted with hot water to obtain polymer pellets having a relative viscosity 1; rel of 3.5.

These two polymers were extruded through a known spinneret for composite spinning having 24 orifices of 0.5 mm. in diameter at a spinning temperature of 310 C. in equal portions. The resultant yarn was taken up at a rate of 300 m./min. to obtain 120 d./24 f. composite undrawn yarn. The yarn was then drawn at 20 C. and at m./min. and a draw ratio of 2.5 using a known draw-twister.

When the resultant composite drawn yarn was treated with steam at 120 C. for one hour under no tension, crimped yarn having number of crimps of 30 and a hard touch was obtained.

EXAMPLE 5 Nyon 6 containing 0.2 percent of titanium dioxide and having a relative viscosity 1; rel of 2.3 as one component, and a terpolyamide having a relative viscosity '21 rel of 2.5 produced by polymerizing 161 grams of 6 M, 12.4 grams of 66 salt and 26.6 grams of 6 T salt (the molar ratio was 91:3:6) as a second component were extruded through a known spinneret for side by side type composite spinning having 10 orifices. The resultant yarn was then drawn to 3.8 times the original length at room temperature to obtain 50 d./l f. composite drawn yarn. The yarn produced no crimp. However, when the yarn was treated with boiling water at 100 C. in a relaxed condition, uniform and good crimps were produced. The yarn had a number of crimps of 45 and excellent bulkiness and extensibility.

EXAMPLE 6 The same polymers as employed in Example were spun under the same condition, and the resultant yarn was then drawn to 3.8 times the original length on a hot plate at 100 C. The composite drawn yarn was treated with boiling water at 100 C. to obtain crimped yarn having a number of crimps of 30. The yarn had slightly smaller crimp strength than that obtained in Example 5, but it was more bulky.

EXAMPLE 7 Nylon 6 containing 0.2 percent of titanium dioxide and having a relative viscosity 1; rel of 2.3 as one component, and a terpolyamide having a relative viscosity 1; rel of 2.4 produced by polymerizing 165 grams of 6 M, 17.0 grams of 66 salt and 18.0 grams of 6 T salt (the molar ratio was 92:4:4) as a second component were extruded through a known spinneret for side by side type composite spinning. The resultant yarn was drawn to 3.5 times the original length at room temperature to obtain 70 d./24 f. composite drawn yarn. The yarn was then treated with boiling water at 100 C. in a relaxed condition to obtain the same crimped yarn having a number of crimps of 50 as obtained in Example 5.

EXAMPLE 8 Nylon 6 containing 0.2 percent of titanium dioxide and having a relative viscosity 1; rel of 2.3 as one component, and a terpolyamide having a relative viscosity 1 rel of 2.4 produced by polymerizing 77 grams of 6 M, 5.0 grams of 66 salt and 18.0 grams of 6 T salt (the molar ratio was 95 :1:4) as a second component were extruded through a known spinneret for side by side type composite spinning having orifices. The resultant yarn was drawn to 3.5 times the original length at room temperature to obtain 50 d./ 10 f. composite drawn yarn. The yarn was then treated with boiling water at 100 C. in a relaxed condition. Thus crimped yarn was obtained having a number of crimps of 28.

EXAMPLE 9 Nylon 6 containing 0.2 percent of titanium dioxide and having a relative viscosity 1 rel of 2.3 as one component, and a terpolyamide having a relative viscosity 1; rel of 2.4 produced by polymerizing 35.0 grams of 6 M, 160 grams of 66 salt and 5.0 grams of 6 T salt (the molar ratio was 33:65:2) as a second component were extruded through a known spinneret for side by side type composite spinning having 10 orifices. The resultant yarn was then drawn to 3.5 times the original length at room temperature to obtain 50 d./l0 g. composite drawn yarn. When the yarn was treated with boiling water at 100 C. in a relaxed condition, uniform and good crimps were produced. The resultant crimped yarn had a number of crimps of 37 and excellent bulkiness and extensibility.

EXAMPLE 10 The same polymers as employed in Example 9 were spun under the same condition and the resultant yarn was drawn to 3.5 times the original strength on a hot plate at 100 C. The composite drawn yarn was then treated with boiling water at 100 C. to obtain crimped yarn having a number of crimps of 28. The yarn slightly larger crimp strength and was more bulky than the crimped yarn obtained in Example 9.

EXAMPLE 1 1 Nylon 6 containing 0.2 percent of titanium dioxide and having a relative viscosity 1; rel of 2.3 as one component, and a terpolyamide having a relative viscosity 1; rel of 2.4 produced by polymerizing 79.0 grams of 6 M, grams of 66 salt and 6.0 grams of 6 T salt (the molar ratio was 60:38:2) as a second component were extruded through a known spinneret for side by side composite spinning having 24 orifices. The resultant yarn was drawn to 3.5 times the original strength at room temperature to obtain 70 d./24 f. composite drawn yarn. When the yarn was then treated with boiling water at 100 C. in a relaxed condition, excellent crimped yarn having a number of crimps of 48 and good extensibility and bulkiness was obtained.

EXAMPLE 12 A terpolyamide having a relative viscosity 7; rel of 2.6 and a melting point of 220 C. produced by polymerizing 226 grams of 6 M, 655 grams of 66 salt and 141 grams of 6 T salt (the molar ratio was 40:50:10) as one component, and nylon 66 containing 0.3 percent of titanium dioxide and having a relative viscosity 1 rel of 2.4 as a second component were extruded through a known spinneret for side by side type composite spinning having 10 orifices of 0.3 mm. in diameter. The resultant yarn was taken up at a rate of 500 m./min. to obtain composite undrawn yarn having a composite volume ratio of 1:1. The yarn was then drawn to 3.5 times the original length on a hot plate at C. to obtain 50 d./10 f. composite drawn yarn. When the yarn was treated with boiling water in a relaxed condition, crimped yarn having a number of crimps of 48, crimp elongation of 120 percent and good recovery and bulkiness were obtained.

EXAMPLE 13 A terpolyamide having a relative viscosity 17 rel of 2.4 and a melting point of 198 C. produced by polymerizing 1,003 grams of 6 M, 77 grams of 66 salt and 169 grams of 6 T salt (the molar ratio was 91:3:6) as one component, and nylon 66 containing 0.3 percent of titanium dioxide and having a relative viscosity 1; rel of 2.4 as a second component were extruded through a known spinneret for side by side type composite spinning having 24 orifices of 0.3 mm. in diameter. The resulting yarn was taken up at a rate of 500 rn./min. to obtain composite undrawn yarn having a composite ratio of 1:1. The yarn was then drawn to 3.9 times the original strength on a hot plate at 100 C. to obtain 70 d./24 f. composite drawn yarn. When the yarn was then treated with boiling water in a relaxed condition, crimped yarn having a number of crimps of 35, crimp elongation of percent, good bulkiness and a feeling equal to that of a known textured yarn was obtained.

EXAMPLE 14 A terpolyamide having a relative viscosity 1; rel of 2.4 and a melting point of 200 C. produced by polymerizing 734 grams of 6 M, 262 grams of 66 salt and 705 grams of 6 T salt (a molar ratio was 65: 10:25) as one component and nylon 66 containing 0.3 percent of titanium dioxide and having a relative viscosity 1 rel of 2.4 as another component were extruded through a known spinneret for side by side type composite spinning having 10 orifices of 0.5 mm. in diameter. The resultant yarn was taken up at a rate of 400 m./min. to obtain composite undrawn yarn having a composite ratio of 1:1. The yarn was drawn to 3.56 times the original length on a hot plate at 120 C. to obtain 50 d./10 f. drawn yarn. When the yarn was then treated with boiling water, crimped yarn having a number of crimps of 60, crimp elongation of 90 percent and excellent crimp strength of 15 mg./d. was obtained.

EXAMPLE 15 A terpolyamide having a relative viscosity 1; rel of 2.4 and a melting point of 180 C. produced by polymerizing 396 grams of 6 M, 131 grams of 66 salt and 282 grams of 6 T salt (the molar ratio was 70:10:20) as one component, and nylon 66 containing 0.3 percent of titanium dioxide and having a relative viscosity 1 re] of 2.4 as a second component were extruded through a known spinneret for sheathed core type composite spinning having orifices of 0.5 mm. in diameter at a composite ratio of ternary copolymer to nylon 66 of 2:3 in such a manner that the cross-section of the resultant fiber was of the socalled kidney type and the copolymer forms the core. The yarn thus obtained was taken up at a rate of 500 m./ min. The yarn was drawn to 3.56 times the original length on a hot plate at 150 C. to obtain 50 d./10 f. composite drawn yarn. When the yarn was then treated with boiling water, crimped yarn having a number of crimps of 42, crimp elongation of 90 percent and crimp strength of 10 mg./d. was obtained.

While the invention has been described herein, with reference to various preferred embodiments thereof, it will be appreciated that variations from the details given herein can be effected without departing from the invention in its broadest aspects. It is to be understood therefore that changes and variations may be made without departing from the spirit and scope of the invention as defined by the appended claims.

What we claim is:

1. A crimped composite fiber of the side-by-side or eccentric sheath-core type obtained by composite-spinning a first component which is poly-e-caprolactarn or polyhexamethylene adipamide, and a second component which is a terpolyamide obtained by polymerization of e-caprolactam (6 M), hexamethylenediammonium adipate (66 salt) and hexamethylene diammonium terephthalate (6 T salt), the ratio of the said two components being 822- 2:8, said terpolyamide having a composite which falls within the area in a triangular coordinate system representing the composition of a copolymer surrounded by the polygon formed by successively connecting by straight lines five points corresponding to the molar ratios of 6 M, 66 salt and 6 T salt of 99.8:0.1:0.1, 0.1:99.8:0.1, 01:70:29.9, 20:40:40 and 60:01:39.9, respectively.

2. A crimped composite fiber according to claim 1 wherein the composition of said terpolyamide falls within the area in a triangular coordinate system representing the composition of a terpolyamide surrounded by the polygon formed by successively connecting by straight lines five points corresponding to the molar ratios of 6 M, 66 salt and 6 T salt of 79.9:0.1:20, 55:35: 10, 40:50:10, 40:30:30 and 69.9:0.1:30, respectively.

3. A crimped composite fiber according to claim 1 wherein the amounts of 66 salt and 6 T salt in said terpolyamide are respectively 0.1 mol percent or more and the sum of both is greater than 1.0 mol percent and less than 10 mol percent.

4. A crimped composite fiber according to claim 1 wherein the composition of said terpolyamide falls within the area in a triangular coordinate system representing the composition of a terpolyamide surrounded by the polygon formed by successively connecting by straight lines four points corresponding to the molar ratios of 6 M, 66 salt and 6 T salt of 65.0:34.9:0.1, 30.0:69.9:0.1, 30.0:60.0: 10.0 and 55.0:35.0:10.0, respectively.

5. A process for preparing a crimped composite fiber which comprises subjecting a component consisting essentially of poly-e-caprolactam or polyhexamethylene adipamide and a component consisting essentially of a terpolyamide obtained by polymerizing e-caprolactam (6 M), hexamethylenediammonium adipate (66 salt) and hexamethylenediammonium terephthalate (6 T salt) to composite spinning in eccentric sheath-core or side-by-side relation, drawing the resultant yarn and then subjecting the drawn yarn to heat treatment, said components being composite spun in a ratio of 8:2-2z8, said terpolyamide having a composition which falls within the area in a tri- 10 angular coordinate system representing the composition of a copolymer surrounded by the polgon formed by successively connecting by straight lines five points corresponding to the molar ratios of 6 M, 66 salt and 6 T salt of 99.8:0.1:0.1, 0.l:99.8:0.l, 01:70:29.9, 20:40:40 and 60:0:1; 39.9, respectively.

6. A process according to claim 5 wherein the composition of said terpolyamide falls within the area in a triangular coordinate system representing the composition of the terpolyamide surrounded by the polygon formed by successively connecting by straight lines five points corresponding to the molar ratios of 6 M, 66 salt and 6 T salt of 79.9:0.1:20, 55:35:10, 40:50:10, 40:30:30 and 69.9:0.1:30, respectively.

7. A process according to claim 5 wherein the amounts of 66 salt and 6 T salt in said terpolyamide are respec tively 0.1 mole percent or more and the sum of both is greater than 1.0 mol percent and less than 10 mol percent.

8. A process according to claim 5 wherein the composition of said terpolyamide falls within the area in a triangular coordinate system representing the composition of the terpolyamide surrounded by a polygon formed by successively connecting by straight lines four points corresponding to the molar ratios of 6 M, 66 salt and 6 T salt of 65.0:34.9:0.1, 30.0:69.9:0.1, 30.0:60.0:10.0 and 55.0:35.0:10.0, respectively.

9. A process according to claim 5 wherein the melting point of said terpolyamide is less than 200 C. and a spinning oil containing up to 40 to C., is employed in said composite spinning and the undrawn yarn is taken up.

10. A process according to claim 5 wherein said drawn yarn is subjected to heat treatment under a load of about 0.5 mg./d.

References Cited UNITED STATES PATENTS 2,071,250 2/1937 Carothers 26078 2,071,253 2/ 1937 Carothers 26078 2,130,523 9/ 1938 Carothers 26078 2,465,319 9/1949 Whinfield et al 26078 2,130,948 9/1938 Whinfield et a1 26078 2,190,770 2/ 1940 Whinfield et a1. 26078 2,931,091 4/1960 Breen 264171 3,399,108 8/1968 Olson 264-171 2,252,555 8/ 1941 Carothers 260-78 2,275,008 3/ 1942 Coifman 264-184 3,271,837 9/1966 Au et a1. 264 3,297,807 1/1967 Settele 264171 3,315,021 4/1967 Luzzatto 264171 3,322,731 5/1967 Cook et a1 264176 F X 3,343,241 9/1967 Gajjav 264168 X 3,365,873 1/1968 Matsumoto et al 57157 3,383,369 5/1968 Ridgeway 26078 3,500,498 3/1970 Fukurna et a1. 264--171 3,526,571 9/1970 Ogata 161175 3,621,089 11/1971 Edgar et a1 264211 3,541,198 11/1970 Ueda et a1. 264-171 3,554,980 1/1971 Ando et a1 161-168 FOREIGN PATENTS 40/25, 173 ll/1965 Japan 264 984,919 3/ 1965 Great Britain 264 669,990 1/ 1966 Belgium 264-171 JAY H. W0 0, Primary Examiner US. Cl. X.R. 

